School gardens in urban Hanoi
We model a decision impact pathway is for school gardens as a general intervention for sustainable children’s food environments in urban Hanoi, Vietnam (Whitney et al. 2024).
Conceptual model of school gardens as an intervention. Should urban Hanoi school boards invest time and money in creating school gardens? Should they invest in formal STEM education as part of these gardens?
Urban Hanoi school garden
Simulation of the school garden intervention options:
The Net Present Value (i.e. current value of the future benefits) of the garden decision options over 5 years of the intervention. For public and private schools the STEM costs are considered to be in the same garden space but with the additional costs and benefits of a full STEM education program. All options are compared to the same years of using the land for something that is not related to the garden, i.e. as a playground or for parking. Here we plot the distribution for the decision and frame the projected NPV.
For public schools:
For private schools:
The same results again but this time as boxplots:
As boxplots and distributions for public schools:
As boxplots and distributions for private schools:
Summary of results for the decision
Summary of the NPVs for the passive education garden and STEM options for private schools:
## NPV_garden NPV_garden_STEM
## Min. :-1420.0 Min. :-4017.3
## 1st Qu.: -171.5 1st Qu.: -488.5
## Median : 382.3 Median : 128.9
## Mean : 692.8 Mean : 346.2
## 3rd Qu.: 1247.1 3rd Qu.: 982.8
## Max. :10218.6 Max. :10175.3Summary of the NPVs for the passive education garden and STEM options for public schools:
## NPV_garden_public_school NPV_garden_STEM_public_school
## Min. :-1420.0 Min. :-4017.34
## 1st Qu.: -285.7 1st Qu.: -460.28
## Median : -184.5 Median : -241.74
## Mean : 288.3 Mean : -56.18
## 3rd Qu.: 590.5 3rd Qu.: 121.57
## Max. : 7138.2 Max. : 6583.17Summary of the child health outcomes for private and public schools:
## health health_STEM
## Min. : 0.0 Min. : 0.0
## 1st Qu.: 304.8 1st Qu.: 278.1
## Median : 768.9 Median : 635.2
## Mean : 836.7 Mean : 651.8
## 3rd Qu.:1227.3 3rd Qu.: 957.4
## Max. :5452.9 Max. :3775.8Summary of the biodiversity outcomes for the passive education garden and STEM options for private and public schools:
## biodiversity
## Min. : 0.000
## 1st Qu.: 4.278
## Median :11.194
## Mean :11.300
## 3rd Qu.:16.864
## Max. :64.952Summary of costs
Total expected costs for a school garden with and without STEM education:
## total_costs total_costs_STEM
## Min. : 87.33 Min. : 143.1
## 1st Qu.: 199.98 1st Qu.: 357.2
## Median : 435.41 Median : 839.6
## Mean : 398.83 Mean : 929.8
## 3rd Qu.: 514.87 3rd Qu.:1252.3
## Max. :1474.13 Max. :5011.9First year expected costs for a school garden:
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## -606.721 -95.383 8.306 65.859 174.797 1869.821First year expected costs for a school garden with STEM education:
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## -943.72 -237.06 -121.76 -77.60 44.09 1772.05Projection to Latent Structures (PLS)
We use Projection to Latent Structures (PLS) model to assess the
correlation strength and direction for model variables and outcome
variables. The Partial Least Squares is fitted with the orthogonal
scores algorithm with pls::plsr.
PLS for private schools:
## Scale for x is already present.
## Adding another scale for x, which will replace the existing scale.
## Scale for x is already present.
## Adding another scale for x, which will replace the existing scale.
PLS for public schools:
## Scale for x is already present.
## Adding another scale for x, which will replace the existing scale.
## Scale for x is already present.
## Adding another scale for x, which will replace the existing scale.
Value of Information
Here we assess value of information with the multi_EVPI
function. We calculate value of information in the form of Expected
Value of Perfect Information (EVPI).
Calculate EVPI:
EVPI for private schools:
## Scale for x is already present.
## Adding another scale for x, which will replace the existing scale.
## Scale for x is already present.
## Adding another scale for x, which will replace the existing scale.
EVPI for public schools:
## Scale for x is already present.
## Adding another scale for x, which will replace the existing scale.
## Scale for x is already present.
## Adding another scale for x, which will replace the existing scale.
Cash flows
Cash flow plots of the garden option without formal STEM education. These are the expected costs for public and private schools over the intervention.
Pareto front
These figures display the Pareto-optimal solutions, representing the best trade-offs among the objectives of biodiversity, child health, and economic return. By focusing on these Pareto-optimal points, the analysis highlights solutions where improvements in one objective cannot be achieved without some compromise in at least one other.
Private schools pareto front
Trade offs for private school pareto:
## Number of Pareto-optimal points for STEM option: 47
## Number of Pareto-optimal points for Garden option: 66
##
## Summary of Pareto-optimal points for STEM option:
## economic_return biodiversity health
## Min. : -576.6 Min. : 718.5 Min. : 7.671
## 1st Qu.: 884.9 1st Qu.:1437.3 1st Qu.:24.519
## Median : 2178.2 Median :1867.4 Median :31.754
## Mean : 2883.6 Mean :2212.3 Mean :31.578
## 3rd Qu.: 4239.7 3rd Qu.:3000.3 3rd Qu.:38.132
## Max. :10218.6 Max. :5452.9 Max. :64.952
##
## Summary of Pareto-optimal points for Garden option:
## economic_return biodiversity health
## Min. :-2564.8 Min. : 402.6 Min. : 7.671
## 1st Qu.: 983.1 1st Qu.:1112.0 1st Qu.:18.787
## Median : 2264.2 Median :1533.7 Median :26.716
## Mean : 2536.1 Mean :1623.1 Mean :28.389
## 3rd Qu.: 4089.9 3rd Qu.:2086.7 3rd Qu.:36.457
## Max. :10175.3 Max. :3775.8 Max. :64.952## $num_pareto_stem
## [1] 47
##
## $num_pareto_garden
## [1] 66
##
## $stem_summary
## economic_return biodiversity health
## Min. : -576.6 Min. : 718.5 Min. : 7.671
## 1st Qu.: 884.9 1st Qu.:1437.3 1st Qu.:24.519
## Median : 2178.2 Median :1867.4 Median :31.754
## Mean : 2883.6 Mean :2212.3 Mean :31.578
## 3rd Qu.: 4239.7 3rd Qu.:3000.3 3rd Qu.:38.132
## Max. :10218.6 Max. :5452.9 Max. :64.952
##
## $garden_summary
## economic_return biodiversity health
## Min. :-2564.8 Min. : 402.6 Min. : 7.671
## 1st Qu.: 983.1 1st Qu.:1112.0 1st Qu.:18.787
## Median : 2264.2 Median :1533.7 Median :26.716
## Mean : 2536.1 Mean :1623.1 Mean :28.389
## 3rd Qu.: 4089.9 3rd Qu.:2086.7 3rd Qu.:36.457
## Max. :10175.3 Max. :3775.8 Max. :64.952Public schools pareto front
Pareto-optimal points for public school options:
## Number of Pareto-optimal points for STEM option: 56
## Number of Pareto-optimal points for Garden option: 71
##
## Summary of Pareto-optimal points for STEM option:
## economic_return biodiversity health
## Min. :-576.6 Min. : 0 Min. : 0.00
## 1st Qu.:1222.1 1st Qu.:1092 1st Qu.:21.40
## Median :2839.3 Median :1469 Median :27.83
## Mean :2978.7 Mean :1823 Mean :28.17
## 3rd Qu.:5080.4 3rd Qu.:2199 3rd Qu.:35.67
## Max. :7138.2 Max. :5453 Max. :64.95
##
## Summary of Pareto-optimal points for Garden option:
## economic_return biodiversity health
## Min. :-2564.85 Min. : 151.4 Min. : 7.671
## 1st Qu.: 66.99 1st Qu.:1003.4 1st Qu.:19.026
## Median : 2078.60 Median :1404.3 Median :24.732
## Mean : 2151.91 Mean :1576.8 Mean :27.016
## 3rd Qu.: 3952.36 3rd Qu.:2064.8 3rd Qu.:35.411
## Max. : 6583.17 Max. :3775.8 Max. :64.952## $num_pareto_stem
## [1] 56
##
## $num_pareto_garden
## [1] 71
##
## $stem_summary
## economic_return biodiversity health
## Min. :-576.6 Min. : 0 Min. : 0.00
## 1st Qu.:1222.1 1st Qu.:1092 1st Qu.:21.40
## Median :2839.3 Median :1469 Median :27.83
## Mean :2978.7 Mean :1823 Mean :28.17
## 3rd Qu.:5080.4 3rd Qu.:2199 3rd Qu.:35.67
## Max. :7138.2 Max. :5453 Max. :64.95
##
## $garden_summary
## economic_return biodiversity health
## Min. :-2564.85 Min. : 151.4 Min. : 7.671
## 1st Qu.: 66.99 1st Qu.:1003.4 1st Qu.:19.026
## Median : 2078.60 Median :1404.3 Median :24.732
## Mean : 2151.91 Mean :1576.8 Mean :27.016
## 3rd Qu.: 3952.36 3rd Qu.:2064.8 3rd Qu.:35.411
## Max. : 6583.17 Max. :3775.8 Max. :64.952Input data for the simulations
Summary
Here we provide a summary of the garden intervention options. We do
this with a summary table of the simulation results. We show the
percentage of missing values as well as the mean, median and standard
deviation (SD) for each output of our model simulations. We use the
gt_plt_summary() from {gtExtras} and with options from
{svglite}. The table shows the name, the plot overview as well as the
number of missing values, the mean, median and the standard deviation of
the distribution for all variables that were fed into the model from our
input table of uncertainty values.
| mcSimulation_table_x | ||||||
| 4 rows x 10 cols | ||||||
| Column | Plot Overview | Missing | Mean | Median | SD | |
|---|---|---|---|---|---|---|
| equipment_cost | 0.0% | 13.8 | 13.5 | 1.3 | ||
| construction_cost | 0.0% | 72.8 | 85.7 | 32.1 | ||
| garden_designing_costs | 0.0% | 11.7 | 11.9 | 1.3 | ||
| teacher_training_cost | 0.0% | 17.4 | 17.7 | 5.5 | ||
| school_board_planning | 0.0% | 7.1 | 7.2 | 1.1 | ||
| teaching_equipment | 0.0% | 9.6 | 9.5 | 1.9 | ||
| compost_starting | 0.0% | 8.3 | 8.4 | 1.9 | ||
| worm_starting | 0.0% | 6.5 | 5.7 | 2.2 | ||
| livestock_establishment_costs | 0.0% | 20.1 | 21.1 | 2.7 | ||
| fishpond_cost | 0.0% | 8.6 | 8.7 | 1.0 | ||
The table shows the variable name, the plot overview as well as the number of missing values, the mean, median and the standard deviation of the distribution for variables that calculated in the model.
The full repository can be accessed at https://github.com/CWWhitney/urban_school_gardens